The ISIS Neutron and Muon Source is a pulsed

neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons behav ...

and

muon A muon ( ; from the Greek letter mu (μ) used to represent it) is an elementary particle similar to the electron, with an electric charge of −1 '' e'' and a spin of , but with a much greater mass. It is classified as a lepton. As wi ...

source, established 1984 at the

Rutherford Appleton Laboratory The Rutherford Appleton Laboratory (RAL) is one of the national scientific research laboratories in the UK operated by the Science and Technology Facilities Council (STFC). It began as the Rutherford High Energy Laboratory, merged with the Atl ...

of the

Science and Technology Facilities Council The Science and Technology Facilities Council (STFC) is a United Kingdom government agency that carries out research in science and engineering, and funds UK research in areas including particle physics, nuclear physics, space science and astro ...

, on the

Harwell Science and Innovation Campus The Harwell Science and Innovation Campus is a 700-acre science and technology campus in Oxfordshire, England. Over 6,000 people work there in over 240 public and private sector organisations, working across sectors including Space, Clean Ener ...

in Oxfordshire, United Kingdom. It uses the techniques of muon spectroscopy and

neutron scattering Neutron scattering, the irregular dispersal of free neutrons by matter, can refer to either the naturally occurring physical process itself or to the man-made experimental techniques that use the natural process for investigating materials. Th ...

to probe the structure and dynamics of

condensed matter Condensed matter physics is the field of physics that deals with the macroscopic and microscopic physical properties of matter, especially the solid and liquid phases which arise from electromagnetic forces between atoms. More generally, the sub ...

on a microscopic scale ranging from the subatomic to the macromolecular. Hundreds of experiments are performed every year at the facility by researchers from around the world, in diverse science areas such as

physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which rel ...

, chemistry, materials engineering,

earth sciences Earth science or geoscience includes all fields of natural science related to the planet Earth. This is a branch of science dealing with the physical, chemical, and biological complex constitutions and synergistic linkages of Earth's four spher ...

biology Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditar ...

and

archaeology Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of Artifact (archaeology), artifacts, architecture, biofact (archaeology), biofacts ...

Background physics

Neutrons are uncharged constituents of

atom Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. Every solid, liquid, gas ...

s and penetrate materials well, deflecting only from the nuclei of atoms. The statistical accumulation of deflected neutrons at different positions beyond the sample can be used to find the structure of a material, and the loss or gain of energy by neutrons can reveal the dynamic behaviour of parts of a sample, for example diffusive processes in solids. At ISIS the neutrons are created by accelerating 'bunches' of protons in a

synchrotron A synchrotron is a particular type of cyclic particle accelerator, descended from the cyclotron, in which the accelerating particle beam travels around a fixed closed-loop path. The magnetic field which bends the particle beam into its closed p ...

, then colliding these with a heavy

tungsten Tungsten, or wolfram, is a chemical element with the symbol W and atomic number 74. Tungsten is a rare metal found naturally on Earth almost exclusively as compounds with other elements. It was identified as a new element in 1781 and first isol ...

metal target, under a constant cooling load to dissipate the heat from the 160 kW proton beam. The impacts cause neutrons to

spall Spall are fragments of a material that are broken off a larger solid body. It can be produced by a variety of mechanisms, including as a result of projectile impact, corrosion, weathering, cavitation, or excessive rolling pressure (as in a ball ...

off the tungsten atoms, and the neutrons are channelled through guides, or

beamline In accelerator physics, a beamline refers to the trajectory of the beam of particles, including the overall construction of the path segment (guide tubes, diagnostic devices) along a specific path of an accelerator facility. This part is eithe ...

s, to around 20 instruments, each individually optimised for the study of different types of interactions between the neutron beam and matter. The target station and most of the instruments are set in a large hall. Neutrons are a dangerous form of radiation, so the target and beamlines are heavily shielded with concrete. ISIS Neutron and Muon Source produces

s by colliding a fraction of the proton beam with a

graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on la ...

target, producing

pion In particle physics, a pion (or a pi meson, denoted with the Greek letter pi: ) is any of three subatomic particles: , , and . Each pion consists of a quark and an antiquark and is therefore a meson. Pions are the lightest mesons and, more gen ...

s which decay rapidly into muons, delivered in a spin-polarised beam to sample stations.

History

The source was approved in 1977 for the RAL site on the Harwell campus and recycled components from earlier UK science programmes including the accelerator hall which had previously been occupied by the

Nimrod Nimrod (; ; arc, ܢܡܪܘܕ; ar, نُمْرُود, Numrūd) is a biblical figure mentioned in the Book of Genesis and Books of Chronicles. The son of Cush and therefore a great-grandson of Noah, Nimrod was described as a king in the land of ...

accelerator. The first beam was produced in 1984, and the facility was formally opened by the then Prime Minister

Margaret Thatcher Margaret Hilda Thatcher, Baroness Thatcher (; 13 October 19258 April 2013) was Prime Minister of the United Kingdom from 1979 to 1990 and Leader of the Conservative Party from 1975 to 1990. She was the first female British prime ...

in October 1985. The name ISIS is not an acronym: it refers to the Ancient Egyptian goddess and the

local name An endonym (from Greek: , 'inner' + , 'name'; also known as autonym) is a common, ''native'' name for a geographical place, group of people, individual person, language or dialect, meaning that it is used inside that particular place, group, o ...

for the

River Thames The River Thames ( ), known alternatively in parts as the River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the second-longest in the United Kingdom, after the ...

. The name was selected for the official opening of the facility in 1985, prior to this it was known as the SNS, or Spallation Neutron Source. The name was considered appropriate as Isis was a goddess who could restore life to the dead, and ISIS made use of equipment previously constructed for the

and

NINA Nina may refer to: * Nina (name), a feminine given name and surname Acronyms * National Iraqi News Agency, a news service in Iraq * Norwegian Institute for Nature Research, on the campus of Norwegian University of Science and Technology * No incom ...

accelerators. The second target station was given funding in 2003 by Lord Sainsbury, then science minister, and was completed in 2009, on time and budget, with the opening of 7 instruments. In March 2011, the Science Minister,

David Willetts David Linsay Willetts, Baron Willetts, (born 9 March 1956) is a British politician and life peer. From 1992 to 2015, he was the Member of Parliament (MP) representing the constituency of Havant in Hampshire. He served as Minister of State for ...

gave a £21 million investment to build 4 new instruments, which are now all in their commissioning phase or fully scheduled instruments. ISIS Neutron and Muon Source was originally expected to have an operational life of 20 years (1985 to 2005), but its continued success led to a process of refurbishment and further investment, intended to advance the facility and extend the life of ISIS through to 2030. According to its Annual Report from 2017–2018, STFC expects the end of the ISIS pulsed neutron source and the associated Second Target Station to be in 2040 and anticipates decommissioning to take 55 years. The cost of radioactive waste disposal could range between £9 million and £16 million.

Science

ISIS Neutron and Muon Source is administered and operated by the

(previously CCLRC). The Science and Technology Facilities council, or STFC, is part o
UK Research and Innovation
Experimental time is open to academic users from funding countries and is applied for through a twice-yearly 'call for proposals'. Research allocation, or 'beam-time', is allotted to applicants via a peer-review process. Users and their parent institutions do not pay for the running costs of the facility, which are as much as £11,000 per instrument per day. Their transport and living costs used to be refunded whilst carrying out the experiment, but aren't anymore. Most users stay in Ridgeway House, a hotel near the site, or at Cosener's House, an STFC-run conference centre in Abingdon. Over 600 experiments by 1600 users are completed every year. A large number of support staff operate the facility, aid users, and carry out research. The control room is staffed 24 hours a day, every day of the year. Instrument scientists oversee the running of each instrument and liaise with users, and other divisions provide sample environment, data analysis and computing expertise, maintain the accelerator, and run education programmes. ISIS is also one of the few neutron facilities to have a significant detector group that researches and develops new techniques for collecting data. Among the important and pioneering work carried out was the discovery of the structure of high-temperature superconductors and the solid phase of buckminster-fullerene. Other recent developments can be foun
here
Construction for a second target station (TS2) started in 2003, and the first neutrons were delivered to the target on December 14, 2007. TS2 uses low-energy neutrons to study soft condensed matter, biological systems, advanced composites and

nanomaterials * Nanomaterials describe, in principle, materials of which a single unit is sized (in at least one dimension) between 1 and 100 nm (the usual definition of nanoscale). Nanomaterials research takes a materials science-based approach to n ...

. The synchrotron itself hosted the International Muon Ionization Cooling Experiment (MICE) for parasitic running from 2008 to 2018. MICE replaced the earlier HEP Test Beam.

Neutron and muon instruments

The instruments currently at ISIS Neutron and Muon Source are:

Target Station 1

Alf
is a crystal alignment facility.
Crisp
is a neutron reflectometer designed for high resolution studies of a wide range of interfacial phenomena. * Engin-X is a neutron diffractometer optimised for the measurement of strain, and thus stress, deep within a crystalline material.
Gem
is a neutron diffractometer that can perform high intensity, high resolution experiments to study the structure of disordered materials and crystalline powders.
Hrpd
is a neutron diffractometer which is one of the highest resolution neutron powder diffractometers of its type in the world.
Ines
is a neutron powder diffractometer, built and managed by the Italian National Research Council (CNR) within the cooperation agreement with STFC.
Iris
is a neutron spectrometer, designed for quasi-elastic and low-energy high resolution inelastic spectroscopy.
LOQ
is a small angle neutron scattering instrument used to investigate the shape and size of large molecules, small particles or porous materials with dimensions typically in the range of 1 - 100 nm.
Maps
is a neutron spectrometer, primarily designed to tackle magnetic and structural excitations in single crystals.
MARI
is a neutron spectrometer, ideal for the study of phonon densities of states in crystalline and disordered systems, and crystal field excitations in magnetic materials.
Merlin
is a neutron spectrometer with a high count rate, medium energy resolution, direct geometry chopper spectrometer.
Osiris
can be used as a neutron spectrometer or diffractometer. It is optimised for very low energy studies and long wavelength diffraction
Pearl
is a neutron diffractometer dedicated to high-pressure powder diffraction.
Polaris
is a neutron diffractometer optimised for the rapid characterisation of structures, the study of small amounts of materials, the collection of data sets in rapid time and the studies of materials under non-ambient conditions.
Rotax
is used for detector and equipment tests.
SANDALS
is a neutron diffractometer especially built for investigating the structure of liquids and amorphous materials.
SURF
a neutron reflectometer one of the leading instruments in the world for liquid interface research.
SXD
is a neutron diffractometer which is powerful in applications involving surveys of reciprocal space, such as phase transitions and incommensurate structures, and also in applications where sample orientation may be restricted.
Tosca
is a neutron spectrometer optimised for the study of molecular vibrations in the solid state.
Vesuvio
is a neutron spectrometer which uses the high intensity of neutrons in the eV energy range (epi-thermal neutrons) to mass-separate the spectra into a collection of nuclear momentum distributions.
EMU
is a µSR spectrometer, optimised for zero field and longitudinal field measurements.
MuSR
is a µSR spectrometer which can be rotated through 90 degrees to enable both longitudinal and transverse measurements to be made.
HIFI
is a high-field muon instrument that provides applied longitudinal fields up to 5T.
Argus
is a muon spectrometer for condensed matter and molecular studies.
CHRONUS
is a muon instrument on the Japanese-owned RIKEN-RAL Muon Facility. ISIS Neutron and Muon Source Target Station 2 entrance

Target Station 2

ChipIR
chip irradiation instrument dedicated to the irradiation of microelectronics with atmospheric-like neutrons.
IMAT
is a neutron imaging and diffraction instrument for materials science, materials processing and engineering.
Inter
is a high-intensity chemical interfaces reflectometer offering a unique facility for the study of a range of air/liquid, liquid/liquid, air/solid, and liquid/solid interfaces.
Larmor
is a flexible small angle neutron scattering instrument that has been optimised for the development of new neutron scattering techniques which use the Larmor precession of neutrons to encode energy or direction.
LET
is a neutron spectrometer optimised for the study of dynamics in condensed matter to understand the microscopic origin of material properties.
NIMROD
is a neutron diffractometer designed to access length scales ranging from the interatomic (< 1 Å) through to the mesoscopic (>300 Å).
Offspec
is a neutron reflectometer that gives access to nanometre length scales parallel and perpendicular to interfaces.
Polref
is a neutron reflectometer designed for the study of the magnetic ordering in and between the layers and surfaces of thin film materials.
Sans2d
is a small angle neutron scattering instruments that can be used to examine size, shape, internal structure and spatial arrangement in nanomaterials, ‘soft matter’, and colloidal systems, including those of biological origin, on length scales of between* 0.25-300 nm.
Wish
is a neutron diffractometer designed for powder diffraction at long d-spacing in magnetic and large unit cell systems, with the option of enabling single-crystal and polarised beam experiments.
Zoom
is a flexible, high count rate small-angle scattering instrument.

In popular culture

The final episode of series 1 of the Sparticle Mystery was filmed on site. The site is also referenced in the book Itch Rocks.

References

External links

ISIS Neutron and Muon Source website homepage

The Science and Technology Facilities Council

UK Research and Innovation
* * View all ISIS neutron and Muon Source publications o
ePubs

ISIS Neutron and Muon Source Science Highlight articles
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